The present invention relates to an improved catalyst for methanation and a method for the preparation thereof. More particularly, the invention relates to a catalyst for methanation having remarkably improved heat resistance and a method for the preparation thereof.
Methanation is a well known reaction by which methane is formed catalytically from hydrogen and carbon monoxide. This reaction is widely utilized for the production of high-caloric fuel gas mainly composed of methane from the so-called synthesis gas or water gas as a mixture mainly of hydrogen and carbon monoxide.
The reaction of methanation is an exothermic reaction evolving large quantities of heat of reaction amounting to 49 kilocalories per mole of the methane produced by the reaction. Therefore it is of imperative importance in the industrial practice of the methanation from the standpoint of energy economy of the process to effectively utilize the heat of reaction in so large a quantity as an energy source. Needless to say, it is desirable to carry out the reaction of methanation at a temperature as high as possible in order to enhance the efficiency of heat recovery and utilization thereof as an energy source. This desirable condition is realized only with a catalyst capable of exhibiting high activity, high selectivity and high durability even in use at elevated reaction temperatures over conventional.
Conventional catalysts for the methanation containing nickel as the active ingredient are in general satisfactory in respect of the activity and selectivity but not suitable for the high temperature reaction rapidly losing their activity when used at an elevated temperature.
Therefore, the methanation reaction by use of a conventional nickel catalyst must be performed with utmost care for the temperature control of the catalyst bed by continuously removing the heat of reaction to avoid excessive temperature elevation which may cause rapid deterioration of the catalyst activity. As a consequence, the efficiency in the recovery of the heat of reaction and the utilization thereof cannot be so high as desired. Various attempts have been made to develop a methanation catalyst having good heat resistance to be suitable for a high temperature reaction but without success.